A liquid crystal display panel mainly consists of an array substrate, a counter substrate and liquid crystal molecules located between the two substrates. Sub-pixel units arranged in a matrix are provided on the array substrate, and each of the sub-pixel units is provided with a thin film transistor (TFT) and a pixel electrode connected to the thin film transistor. A common electrode and color filters in a one-to-one correspondence with the respective sub-pixels are arranged on the counter substrate. Upon the liquid crystal display panel being cell assembled, an alignment is required to be performed between the respective color filters on the counter substrate and the respective sub-pixel units on the array substrate. A bias easily emerges during the alignment. In order to avoid generation of the alignment bias, a structure with the color filters directly arranged on the array substrate (COA, CF on Array) appears.
Presently, the existing COA structure mostly makes the color filters simply directly be superposed on the array substrate. As an example, the COA structure in the mode of an Advanced Super Dimension Switch (ADS), as illustrated in FIG. 1, has a structure on the array substrate, which comprises: a gate electrode 102 and a common electrode line 103, a gate insulating layer 104, an active layer 105, a source electrode 106 and a drain electrode 107, a first insulating layer 108, a black matrix 109, a color filter 110, a pixel electrode 111, a second insulating layer 112, and a common electrode 113, which are arranged sequentially on a base substrate 101. The common electrode 113 passes through the via hole a which penetrates through the gate insulating layer 104, the first insulating layer 108, the color filter 110 and the second insulating layer 112, and electrically connect to the common electrode line 103.
The array substrate of the above structure requires patterning processes by using 10 masks during the manufacture. Concretely, the steps for patterning by using masks are manufacturing the pattern of the gate electrode 102 and the common electrode line 103, the pattern of the active layer 105, the source electrode 106 and the drain electrode 107, the pattern of the gate insulating layer 104 and the first insulating layer 108, the pattern of the black matrix 109, the pattern of the color filter 110, the pattern of the pixel electrode 111, the pattern of the second insulating layer 112 and the pattern of common electrode 113. As the color filter 110 generally consists of homochromatic filters with the primary colors crosswise arranged, which are red, green and blue, it is requires patterning with 3 masks, respectively.
In the above structure, the non-transparent common electrode line 103 and the gate electrode 102 are arranged in the same layer. On the one hand, aperture regions of the respective sub-pixel unit can be occupied, which influences the aperture ratio, and on the other hand, the common electrode 113 is required to electrically connect to the common electrode line 103 by a deeper via hole a, and as this via hole a penetrates the gate insulating layer 104, the first insulating layer 108, the color filter 110 and the second insulating layer 112 with different materials, the formation of the via hole requires several patterning processes during the manufacture, which also increases the difficulty of the entire manufacturing process.
To sum up, problems that the difficulty of the manufacturing process is high and the aperture ratio is low exist in the array substrate in the ADS mode of the existing COA structure.